| In view of the clinical needs of minimally invasive and precise fracture reduction surgery,based on the parallel integrated robot of fracture reduction surgery and rehabilitation developed by our research group,this thesis carries out research work such as robot fracture reduction trajectory planning method and automatic realization,which mainly involves segmentation and reconstruction of adhesive bone tissue,bone collision detection,muscle force simulation,fracture reduction trajectory planning,software development and system integration,etc.The main achievements of this thesis are as follows:1.Segmentation and reconstruction of broken bones based on CT data.Analyze the principle of CT imaging and the storage format of CT images,and realize the parsing and rendering of DICOM data with the help of ITK and VTK data processing pipelines.Based on the threshold segmentation and the improved OTSU method,the non-interesting regions such as muscle and skin are removed,and the region growth algorithm is used to complete the extraction of the healthy side bone and broken bone.Based on the interactive erasing tool and alternate multi-region growing segmentation method,the segmentation of adhesion bone tissue is realized.Using the marching cubes algorithm,three-dimensional reconstruction is performed to obtain the models of contralateral bone,proximal bone and distal bone.2.Trajectory planning of fracture reduction.The initial and target postures of fracture reduction were defined with the reference of the patient’s contralateral bone model.The collision detection threshold is defined,and the closest pair of points between broken bones is quickly found based on the octree search algorithm,so as to realize the collision detection of broken bones.A personalized fracture muscle model is established by the standard model of OpenSim through scaling features,and the muscle force in the reduction process is obtained in real time.The trajectory search node and evaluation function of A* algorithm are designed to realize trajectory planning with the constraints of no collision of bones,minimum muscle tension and shortest path.With the help of VTK camera model and mouse interaction events,the mouse interaction control is designed and developed for interactive planning of reduction trajectory.A comparative experiment between the automatic and interactive trajectory planning methods was carried out.The average planning time of automatic method is only 3.2s,which is two orders of magnitude less than that of the interactive method.The average reduction path length was 24.3 mm,a decrease of 36.7%,and the average muscle force was 96.4 N,a decrease of 16.2%.The experimental results show that the automatic trajectory planning takes less time,is more efficient,and is safer and more reliable.3.Development of reduction planning software for an integrated robot for parallel fracture surgery and rehabilitation.Based on the CT data,the relative poses of the broken bones and the parallel robot were calculated,and the length of each struct of the robot during the reduction process was obtained through the inverse position solution.Analyze software requirements,divide functional modules,sort out business logic,design storage structure and user interface,and develop a set of reduction trajectory planning software for parallel fracture surgery and rehabilitation robots based on tools such as C++,QT,VTK,ITK,and Open Sim.Model experiment was carried out to verify the effectiveness of the robot reduction trajectory planning method and software system.In this thesis,for the integrated robot of parallel fracture reduction surgery and rehabilitation,a robot reduction trajectory planning method integrating muscle force simulation,collision detection and path optimization is proposed,and a reduction trajectory planning software system is developed,which improves the efficiency and safety of robot reduction surgery,and provides theoretical and technical support for minimally invasive and precise fracture reduction treatment. |
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